Improvement in steam-engine governors



cicli, Stairs strut @inline Leners Param N 95,043, dated 00mm- 5, 1869.

IMPROVEMENT IN STEAM-ENGINE GOVERNORS.

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The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern Be it known that I, WILLIAM WicicnnsnAM, of Boston, in the county of Suffolk, and State of Massachusetts, have invented a new and useful Steam- Governor; and I do hereby declare that therfollowiug is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon. Y

The first feature of my invention relates to a tinieshai't, and its connection with the valve; and consists J of a shaft so connected with the valve, that while it turns a given number of revolutions in a given time, it will impart to the valve the. sarne number of' movements forward and backwardl in the same time.

The second feature of my invention relates to two shafts, in connection with the valve and cut-olf slide, one governed by time, and the other rnoved and governed by the main shaft of the engine, thetime-shaft giving motion to the valve, and the engine-shat giving motion to the cut-ofi slide, and these all so arranged that when the two shafts have their ecoentrics, cranks, or cams, which give motion to the valve and cut-oli' slide, on the same side, as they revolve together the port will be open nearly the whole stroke of the piston, aud when the vengine-shaft is in advance of the time-shaft to any degree within an arc of` one hundred and eighty degrees, (to which it' is limited) the port will be closed during the last portion'of the stroke of the piston to nearly the same degree, and, by thus diminishing the` steam whenever the engine-shaft makes any advance on the time-shaft, and this diminution of steam becoming greater' according lto the greater degree of advance, the engine-shaft is substantially and practically held to or governed by time.

The' third feature ot' my invention relates to the equalization of the force of the spring onthe fan,

which force is constantly liable to variation; and consistsin applying the force nearer to the centre of inotion of' the fan, proportionally as the force increases.

The fourth feature ot' my invention relates to the automatic adaptation o't' the surt'ace of the fau to the changing resistance 'of the-air by temperature; and

consists in so connecting the fans with metallic bars,

formed bt' metals of unequal expansibility, so arranged and formed that by this unequal expansion the etfective surface ofthe fan willbe so varied that while the resistance ot' the air varies, its .resistance on the fan will be always the same, with the same velocity of the fan.

The lifth feature of myinvention relates to the form and construction of thevfan;v and consists in making the fan with two series of leaves and 4spaces, one series attached to the bar which has the greater expansion, and the other attached to the one which has the less expansion, in such manner that the unequal expansion of the bars will cause the leaves oi' one series to :par-

tially cover the spaces ofthe other series, therebjY enlarging the effective surface ofthe fan.

The sixth feature ot' iny invention relates to the device by which any desirable speed may be fixed to the engine, which spec-.d will be continued uniformly by the governor; and consists of a ring around the shaft, controlled by the engine, to which the inner end ofthe spring is attached which drives the iinr, so arranged on the shai't that it can be turned to any position o n the shaft, or any number of times around the shaft, and then xed by set-screws, giving the spring. any degree oi'l tension, and thereby giving the time-shaft, which turns with the fan, any desirable speed, which speed is given to the engine-Shad. l

Figure l is a perpendicular and longitudinal section through the reii'line A, showing the cylinder, piston,

ports, balance-valve, and the eccentric which works' it, and the machinery/above, which impels it and regulates its movement; also, the cut-oit' slide within the valve, which operates as an automatic cut-oii`, with the eccentric, and machinery for working the sau-re.,A

Figure 2 is a horizontal section through the steamchest, in the red line B. l

Figure 3 is a perpendicular cross-section through. the steam-chest, in the red line i).

Figure 4`is a horizontal section ot' the two eccentricshafts, iu the red line l), and an under-side View oi'v Athe spring, the fans, and other machinery above this section.

Figure 5, sheet 2, is a horizontal section of thev fans, composed of three sheets, the middle one of steel and the two outside ones ot' zinc, in the red lilies G, and in the lowest temperature, having the steel' and zinc plates, forming the fan, ot' even length.

Figure 6 is a side elevation ofthe same.

Figure 7 is asection ofthe same in the red line H, after the temperature has been suliiciently raised to expand the zinc sheets in excess ot' the steel sheet to such -a degree as to cause lthe zinc leaves of the fan to extend hall way across the spaces between the leares of the steel part ot' said fan.

Figure 8 is a side elevation of one endI ofthe saine.

Figure 9, sheet 3, is a horizontal section inftlre red line E, and illustrates the position oi' each eccentric' relatively to`the other, (their elongated sides in the same direction,) which keeps the port open while the piston moves the whole length of the cylinder, the time the port is open being represented by thererl line or aro l.

Figure 10 illustrates the same, when the shaft-ccceutlic is ibrty-live degrees in advance of the time-eccentric, the red arc J, of one hundred and thirty-tive degrees, representing the portion of a revolution of the shait in which the port would be open.

FigureA 11 shows the same, when the shaft-eccentric is ninety degrees in advance of the time-eccentric.

Figure 12 shows the same, when the shaft-eccentric is in advance of the. time-eccentric one hundred and thirty-tive degrees.

Figure 13 is the same as iig. 9, if both eccentrcs should revolve together one-eighth round.

Figure 14 is the same, as having revolved one-quarter round. i

Figure 15, as having revolved three-eighths round.

Figure 16, as having revolved one-half round; and it will be observed valve is open, and in 9 and 16 it is closed. i

Figure 17 is the same as fig. 11, revolved one-eighth round, and

Figure 18, the same as g. 11, revolved one-quarter round.

M is the cylinder.

N is the pistonshead."

O is the balance-valve.

P is the cut-off slide.

Q is the top ofthe steam-chest.

t 1t are the two sides of the same.

S is the eccentric which gives motion to the valves O.

'l is a gear on the shaft U, turning the gear V, and its hollow shaft V, and the eccentric Y, and all so arranged that the eccentric Y will revolve once round to one round of the Inain shaft of the engine.

`Z Z are the two exhaust-ports. v

a is the pipe leading from the boiler to the steamchest.

b is the ily-whcel.

c is a spring, attached to the shaft XV by the set screw ll in the ring fw, while its outer end is secured to the pin e on the slide f, which is fitted movably on one of the arms of the fan.

The ring w is so formed and fitted on to the shaft XV, and so attached to the inner end of the spring c, that it can be turned to any position on the shaf't, or any desirable number of times around the shaft, carrying the end ofthe spring along with it, and thereby giving 4any desired degree of tension or power to the spring, as, by this governor, the speed of the engine has a direct relation to the force this spring exerts upon the fan, and accordingly, when this ring is turned to the position on the shaft which will give the desired speed to the engine, the set-screw d, and the engine continues to run with a uniform inotionat the rate of speed thus xed.

li is the shaft to which the fans are attached,`and which has on its lower end the eccentric S, which gives motion to the valve O. rlhese are so arranged that when the shaft XV revolves, (by means of the4 gear T, which turns it onceround to each round of the main shaft ofthe engine,) it carries the spring c around with 4lit, which, in turn, by means of its elastic force, carries the fan around in the same direction, being attached to it by the pin c, so that the shaft W', the spring c, and the fan, have a common motion together so long as the` resistance of the air against the fan, together with the resistance of the work on the eccentric S, is equa-l to the tension or elastic force of thc spring,

.which limits and xes the velocity of the fan;` then,

if the work ofthe engine diminishes, or the steam is raised, the shaft \V and its eccentric Y will move in advance of the shaft It and. its eccentric S.

But it will be perceived that when `this is the case, the spring c will be wound up further,l and its elastic force on the pin e will be greater; and if this greater force is exerted on the arm of the fan at the same dis tance from its centre of motion, it would cause the fan to move faster whenever the shaft W is in advance of shaft 7l.

that in figs. 13, 14, and l5, they it is secured to this position by` a disk, g, to the upper end of the shaft W, and have placed a roll, i, on the'pin e, to work in the groove j in the disk g, and, by observing the drawing in iig. 4, it will be seen that this groove j is nearer to the ccntre 4of the disk, at the opposite end from the roll t, (as shown in the drawings,) than at the place of said roll. The purpose of this is to equalize the varying force of the springen the fan, by having it, as it is increased, applied to the arm of the fan nearer to its centre of motion, and insuch relation as to make the real force of the spring on the fan uniform, however much theV shaft WV may be in advance ofthe shaft h.

By referring to the same drawing, it will be seen that the groove j extends yonly half way round in the disk-y, so that the degree of advance of the shaft lV, g beyond the shaft h, is limited .to one hundred and eighty degrees, which is sufficient for the purpose of my invention; as, in the rst position, that is, with the greatest elongation of both eccentrics in the same direction, they will so act ou the valve O `and slide I as to keep the port open during the entire stroke of y thc piston; and, by having the shaft W one hundred and eighty degrees in advance ofthe shaft` h, the port will be closed the whole time, and between these points the port will be open from the beginning ofthe stroke of said piston, but will be closed during the last portion of the stroke in proportion to the degree of advance which the shaft NV has beyond the shaft la., which will be further illustrated and explained.

k k are the two ports to the cylinder.

l L are the two spaces in the valve connecting the steam-chest with said ports.

an m are the exhaust-ports', which have their outlet through Z Z. Now, in case the force which gives motion to the fan is uniformly the same, and the eccentric S has the same work to do during each revolution, and the air furnishes a uniform -resistance at any given` speed, then, when'this fan is -set in motion by the force of this spring c, the motion of the fan will increase until` the resistance of the air against it, together with the resistance of the valve O against the eccentric, is just equal to the force of the spring, and then a uniform motion to the shaft h. will ensue, the constant y force balancing a constant resistance, and` this uni-- formity of niotionwill continue so long as the force remains the same, (forwhich I have already provided,) and the air continues to furnish a uniform resistance to the fan at any given speed. But this is liable` to change by changefof temperature, the air becoming less dense and furnishing less resistance as the temperature is raised. For instance, if the temperature is raised doubled, and its powerof resistance reduced to onehalf, and for a fan moving with a uniform velocity through the air having its temperature thus increased, should have the surface doubled also, in order to neet the same resistance, and for each degree of in# crease of temperature, its surface should be increased TlJ-T, or nearly so.

Forthis, I have provided a device, by which the surface of the fan is automatically increased with the increase of the temperature, thereby compensating for the diminishing resistance Yof the air as its temperature is increased.

On sheet 1, figs. 1 and 4, this device is shown in section in iig. 1, and a bottom vicw is shown in fig. 4.

lhe fan is made of inanydeaves, with intermediate spaces between them, and two sheets thus formed are placed together, and are so arranged that one will be moved in one direction, andthe other in the other direction, in such manner that thelcaves of one will fill the spaces of the other by the unequal expansion of metallic bars. f/

r r r rare zinc bars,'whicli are "ittached at their:

inner ends/to the shaft h, and at their outer ends to 491 Fahrenheit, the volume of the air is face of the fan.

the steel bars s.s s s, which, in turn, have their inner .ends attached to inner -ends of the zinc bars t. t, and theenter ends of these areattaclid to the slides p p', in -such manner as to give an outward expansive` motion equal to the egzpansion of the zinc bars lr r fr r and t t, minus the expansion of the s teel bars s s, Svc.

The slide p is attached to the'fan-leaves o o' o and the steel bar il, which extends to' the slide qon the other arm of the fan, and these slides q and q are at Jcached to the fans n n ,n and n n n', and all arranged in such manner that the fans o o o and o' o' o' will, by

expansion, be movedontward, as the arrow-pointsat` p p indicate,'and the fans-n n n and nn n' will be moved inward, as the arrow-points at g. q' indicate, thereby causing the two series of fan-leaves to cover each others spaces as the temperature rises, and in that way increase the eiective surface ofthe fans; and these leaves should be made of such a width that the expansive motion of the bars would increase the lei'ective surface of the fan .by any given increase of temperature, in the same ratio as the diminution of the resistance of the air bythe same increase of tem-` perature.

I do not confine myself to steel and zinc bars for the. arms of the fan, but may use any'two metals which have a suticiently unequal expansion for the purpose. 0n sheet ,2, a more 4simple form of the'fan andthe expansion-bars is shown, in which the arms and the fans are composed of three bars, the two outside ones of zinc, and the middle one of steel,

Fig. 6 -shows a section through the leaves in the red lineG, showing the relative position of the leaves before any expansion has taken place.

Fig. 7 is a side elevation Vof the same.

Fig. 8 shows a section of the leaves of the fan in the red line H, after the bars have been expanded.

Fig. 9 is a side elevation of one end of the same.

Inthis arrangement', the zinc bars r and r l1av e leach a fan formed on one end, While-the other end is attached toV one end of the steel bar between them, one, r', iiveted to the end of theste'el bar at s', and its other. end formed into a fan corresponding to the fan on the steel bar 'v at the same end, andthe lzinc'har r is attached to the other endl of the steel bar ,v at s, and all 'arranged in such manner that 'when the temperature is raised, the bars r and' t', heilig securedtogether at s, will have an unequal. expansion, and thereby canse the leaves o o o on the bar rr to advance over the spaces of the leaves n n-fn in the steel bar, and the bar lr., infllike manner, being secured to. the

end of the steel plate c, at s', will, when,heated,have

a greater expansion than the steel bar c, and the leaves ofA its fan o o' o will advance over the spaces between the leaves n 'n n o'n the,'steel bar, as "shown in igs. 8 andi), thereby increasing the eiiective snr- ,.Now, as the air expands to double itsjvolnme by raising its temperature 491 Fahrenheit, its resistance against a fan ofthe same surface will be one-half; therefore, the 4eiiective surface ofthe fan must be' doubled to meet the same resistance, according to theory; and for ench'degree of temperature the fan must be increased in surface :f-f; and, as zinc expands by raising'its temperature from the freezing tothe boiling-point of water 15g-' of its lengt-h, andas steel, (not hardened) by the same increaseof temperature, expands d, ofits length, the diierence of expansion can be computed, and-the width of the leaves ofthe ian estimated, by which the expansion of any given length of bars will increase the eiifective surface of the fan,for the purpose of compensating vfor the diminished resistance of the air byqits increased temperature; or the width of these leaves-"maybe ascertained .by a purely practical way.

Take a fan made of a single sheet, as the steel sheet.. A

is shown-on sheet 2, and tryit under different tempera-tures, and ascertain the difference' of surface for dii'erent temperatures, giving the same speed to the fan While it is impelled by a uniform force, and this will give the necessarydata to' adjust the leaves of .eccentrics, and theeifect of these different positions on the. valve in opening and closing it, and in the operation of the cnt-'ono slide in connection with said valve.

Fig. 9 shows theposition ofthe two eccentrics, the same as in figs. l and 2, thel twoeccentrics having their elongated sides in the 4same direction, and the valve and cnt-off slide are in such position as to open the passage for the steam into the cylinder, immediately on the movement of the two eccentrics in the direction indicated by the arrow-point on the same, and while they revolve through an arc of one hundred and eighty degrees, at which time it is closed, and the valve will be opened yat the opposite end of the cylinder, which, in turn, will remain `open during half a revolutionof the eccentrics', or during the whole stroke of the piston, as indicated by the red arc I.

In iig. 1'0, as' in g. 9, the valve is in a position to open 'when the -eccentrics begin to revolve; but, in this ca'se, the eccentric Y, which moves with the engine-shaft, is forty-five degrees in advance ofthe timeeccentric S, and they can move only three-eighths of a revolution before the port .is closed, as indicated by the red arc J; and in iig. l1 the shaft-eccentric-Yis ninety degrees in advance of the time-eccentric S, and they can revolve only one-fourth of a revolution before the steam is cutv on, as-indicated by the red arc K; and again, in fig. 12, the shatteccentric Yis threeeighths of a revolution in advance of the time-ecce, l

tric, and consequently the steamWill-be cnt off at one-fourth of thez stroke, as shown by the red arc L.

The ngs.'9, 13, 14, 15, and 16, show the positions of the valve O and the cnt-o' I. relatively to thel port K, every eighth of the round through half of a rev lution from the iii-st posit-ion in fig. 9, where the valve is closed, to fig. 16, where it is again closed, the intel'- vmediate ones, figs. 1 3, 14, and 15, being open, having the opening in the valve at l immediately over 'the portK, and not being covered 'by the cut-oh" slide; and during this half revolution the twoeccentxics turn together, lthat iscont inne their greatest' elongation in the samedirection, as't-heyboth revolve with-the same speed, and'consequently the valve is open during the whole stroke ofthe piston, or withinY a fraction of it.

Again, in tig.' 11 the elongated sides '.of the eccentrics are atright angles, the shaft-eccentric'is inadvance of the time-eccentric ninety degrees; but, holding that positit'm,v andturningtogether through fortyfive degrees, gives'the position seen in'tig.17-, Where the valve' lis open, and turning. again forty-live dc'v grees `gpves-the position. in iig. 18, where the valve is again'closed. A

The ily-wheel b may be found necessary to maintain a uniformity of motion through the whole revolution of the time-eccentric, as itswork will be in a measure unequal in its progress round. f

Having .described thc parts, I will now describe the operation.- f

The steam islet into the steam-chest through the pipe u., and the shaft h, is turned slightly to `admit steam" into the cylinder, back of the pistou-head N, which moves it to the other end of the cylinder, and.,

puts the whole machine in motion.-

The shaft U, being so communicated with the main shaft of the engine as to revolve in the same time with it, turns the gear V and the shaft W with an equal s eed.

pAttached to this shaftW is a spring, c, which spring' has its other end attached to the arm of the fan through the pin e, and thus imparting motion to the fan by a constant yielding force, which force is equalized by the pin e being moved toward the shaft h, when the shaft W moves in advance of it, which would increase the powerof the spring were it not for this inward movement of thepin, the pin e passing round in the groove j, thereby giving a uniform force to the fan through the spring c. y

Then, assuming that the force which gives motion to the fan, and the shaft h to which it is attached, is uniform, and assuming that the resistance of the work done by the eccentric S, including the friction, is the same for each revolution, and also assuming that the resist-ance of the air against the fan increases in proportion to the square of the velocity of the fan, then it is clear that whenthe engine is set in motion, the velocity of the fan will increase until the resistance of the work of the eccentric S in moving the valve, added to'the resistance of the air against the fan, will just balance and equal the force of the spring c,'a t which time a uniform motion'of the shaft h will. ensue, and be maintained so long as these two balancing-forces remain the same.

Now, as the resistance of the work to the eccentric S, after the machinery has become worn smooth, can be counted on as substantially the same, the only factor liable to change is the resistance of the air, which, as we have before s een, changes with its temperature;` but as this has been comp nsated. for by the increase of the effective surface ofY `he fans by metallic expansion, as before described, this resistance is made unix form and equal through alll changes of temperature which ,the engine-room would'be liable to. f

This being the case,.we then have a uniform motion in the shaft h, which, of course, alwaysgives the same number of movements to the` valve O in a given length of time; and as the relationsvl of tle vvalve 'and cut-oli?` slide,and the eccentrics which' give them motion, are such that when the elongated sides of' the two eccentrics S and Y are maintained on the same side, and move with each other, the valve or passage from the steam-chest to the cylinder'will ,be open during the whole stroke of the piston, or within a fraction of it;

and as when .the elongated side of the eccentric Y,

which moves with the main shaft of the engine, is in advance of the eccentricS one hundred and eighty degrees, the valve will be constantly closed; and as whenr the eccentric Y is in advance ot" the eccentric S, any' degree betweenethese two pointsjof coincidence .and opposition,*the valve Vwill be closed during the said proportion of the stroke of the piston, asits degree of advance, or sufliciently near 'for the purpose, it there- 4fore follows that the motion of the shaft It practically governs the motion of thev main shaft of the engine, and will hold it to al given number of 4revolutions in a given'time. A

l 4Although the fan, using the corrections which I have made, is `achcap and convenient method, and, I think, sufiiciently accurate for regulating the time of the motion of the shaft h, yet I do n'ot confine myself to do the work during that length of time.

to this method of giving time` to this shaft, as any clock can be used. Y

The device well known by astronomers as the springgovernor, by which the motion of the transit-instrument is connected with and regulated by any timepiece or chronometer, may be substituted for this fan, and the time of the best chronometer thereby made to govern the motion of the shaft h, and accordingly hold themain shaft of the engine `to the most correct time, and though more perfect in time, the expense would be much greater.

marine engine, in case the screw or wheels should get out ot' the water, by my governor the whole of the steam is cut off invabout one round of the main shaft of the engine, thereby preventingany `speed, that would do damage.

The pin e would, in that case, pass to the opposite end of the groove j, from its position shown in fig. 4, when it andthe fan would be carried round with the same speed of the fly-wheel, keeping lthe valves coul tinually closed.

rlhe screw of a steamer, getting out of `the water, would meet with 'a similar and equally harmless result. i i

The economy of steam is another advantage, as, by my governor, only just enough of 'steam is admitted into the cylinder at each stroke of the piston This is the ultimatum of good economy, as it not'unfrequently i happens that steam-engines with bad governors waste from one-fourth to one-third of their steam.

Simplicity, compactnessr andismall cost, are among its good qualities; -but the simple device for which the engine is held to time, is the leading idea of it;

This governor can be applied equally well to waterpower as to steam. i

Having thus explained my invention,

What I claim, and desire to secure by Letters Patent, is-' l l. The combination` of thevalve O with the timekeeper and shaft h, whereby the valve-movement shall be regulated by the time of the time-keeper, substantially as herein set forth. l

2.-'The combination-of the valve O, slide I, and time-keeper, whereby the movement ofthe `valve shall be controlled by the time-keeper, while the movement ofthe cut-off slide may be controlled by the main `shaft of the engine, substantially as set forth.

3. The combination-of the slide j, pin e, and groove j, substantially as herein described.

4. The construction and arrangement of the fan and .its immediate Vco-operative parts, as herein set forth, whereby the eiective surface of the fan shall automaticallyvary .in accordance with the unequal expansion of the metallic bars, as herein made known.

5. The"construction and arrangement of the fans and their co-ordinate devices,.whereby the respective leaves of the fans may occupy` more or less of the spaces, and thereby increase or diminish the effective surface, substantially as herein described..

6. The combination of the ring w with the lspring `c, in the manner and for the purpose set forth.

Witnesses: WILLIAM WICKERSHAM.

A. D. PARKER, LYMAN MASON.

y In case the belt should break or slip off, or, in a 

